1. Field of the Invention:
The apparatus of the present invention relates to transparent slide viewer apparatus and, more particularly, to slide viewer apparatus having a rechargeable battery and which is compact, relatively inexpensive to manufacture, and which distributes light evenly over substantially the entire area of a slide or transparency.
2. Description of the Prior Art:
Slide viewer apparatus of the prior art comprises many different types, most of which include four standard components. One of the standard components is a housing in which a light source is located, and which receives a transparency or slide. The second standard component is a lens for enlarging the slide, usually a thirty-five millimeter slide, to produce an image substantially larger than the original slide. The third common element is a light source disposed behind the slide for illuminating the slide. The fourth component is a light diffuser disposed adjacent the light source for diffusing the light from the lamp over the slide. Typically the diffuser is simply a piece of frosted glass.
There are typically three types of electrical systems for such slide viewer apparatus, one comprising simply a common dry cell, the life of which is relatively short. A second type of light source is a bulb which may be plugged into an ordinary 115 volt household electrical system. The third type of electrical system includes a rechargeable battery, which offers the best features of the two electrical systems just mentioned. The rechargeable battery electrical system may simply be plugged into an ordinary household 115 volt outlet for recharging the battery, and the user is accordingly free from the problems of continually purchasing new dry cell when the cells or batteries lose their power.
Another inherent problem with prior art slide viewing systems is the provision of an adequate light source which provides a substantially uniform area of illumination which coincides with the area of a slide. Various types of diffusers have been used with a single light source, but regardless of the type of diffuser elements used in the prior art, the slide is illuminated unevenly.
In the prior art slide viewing systems, the diffuser is disposed between the light source and the slide. Since the light source is a filament in a bulb or lamp, it is difficult to diffuse the light evenly over an area which is substantially larger than the filament. The filament, for all practical purposes, comprises a single point light source. The provisions of a diffuser of the prior art between the single point source of light and the slide virtually ihherently results in uneven illumination of the slide.
The apparatus of the present invention overcomes the problems of the prior art by interposing a solid diffuser/reflector block between the light source and the slide, adjacent the light source, but not in direct alignment between the light source and the slide. The diffuser block in turn conducts and reflects the light from the light source from a wide surface area directly onto and through the transparency for substantially uniform or even illumination of the transparency.